board: samsung: e850-96: Split LDFW loading and init

board: samsung: e850-96: Split LDFW loading and init

The LDFW firmware loading is done in two steps:

  1. Read the firmware binary from some block device
  2. Provide it to EL3 monitor software via an SMC call, so it can copy
     it to a Secure World memory and start using it

Let's split the load_ldfw() function by two functions correspondingly,
to reflect that process better:

  - load_ldfw_from_blk()
  - init_ldfw()

It can be useful in case when the LDFW binary should be obtained from
some different media, e.g. downloaded over USB during USB boot.

No functional change.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>